Re: [PATCH] staging: rtl8723au: change typecast to match type returned by htons()

From: Jes Sorensen
Date: Mon Nov 10 2014 - 16:09:59 EST


Arend van Spriel <arend@xxxxxxxxxxxx> writes:
> On 10-11-14 21:21, Jes Sorensen wrote:
>> Chris Ruffin <cmruffin@xxxxxxxxx> writes:
>>> Using a u16 pointer typecast for a result from htons() results in
>>> the following warning from sparse:
>>>
>>> drivers/staging/rtl8723au/core/rtw_xmit.c:1279:36: warning:
>>> incorrect type in assignment (different base types)
>>> drivers/staging/rtl8723au/core/rtw_xmit.c:1279:36: expected
>>> unsigned short [unsigned] [short] [usertype] <noident>
>>> drivers/staging/rtl8723au/core/rtw_xmit.c:1279:36: got restricted
>>> __be16 [usertype] <noident>
>>>
>>> This patch fixes the issue by using an endian-specific typecast
>>> that will always match the type returned by htons().
>>>
>>> Signed-off-by: Chris Ruffin <cmruffin@xxxxxxxxx>
>>> ---
>>> drivers/staging/rtl8723au/core/rtw_xmit.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> Looks fine to me
>>
>> Signed-off-by: Jes Sorensen <Jes.Sorensen@xxxxxxxxxx>
>>
>>>
>>> diff --git a/drivers/staging/rtl8723au/core/rtw_xmit.c
>>> b/drivers/staging/rtl8723au/core/rtw_xmit.c
>>> index a0f7e27..44ef55c 100644
>>> --- a/drivers/staging/rtl8723au/core/rtw_xmit.c
>>> +++ b/drivers/staging/rtl8723au/core/rtw_xmit.c
>>> @@ -1276,7 +1276,7 @@ s32 rtw_put_snap23a(u8 *data, u16 h_proto)
>>> snap->oui[0] = oui[0];
>>> snap->oui[1] = oui[1];
>>> snap->oui[2] = oui[2];
>>> - *(u16 *)(data + SNAP_SIZE) = htons(h_proto);
>>> + *(__be16 *)(data + SNAP_SIZE) = htons(h_proto);
>
> Could (data + SNAP_SIZE) be on a unaligned address?

It shouldn't but probably better to take it into account. I am moving
things around in this code right now, so I'll just fix it in a follow-on
patch to this one.

Cheers,
Jes
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